Arrangement in zig-zag sewing machines for sewing button holdes automatically



E. SCHENKENGEL Jan. 14, 1964 ARRANGEMENT IN ZIG-ZAG SEWING MACHINES FOR SEWING BUTTON HOLES AUTOMATICALLY 2 Sheets-Sheet 1 Filed March 26, 1962 Jan. 14, 1964 E. SCHENKENGEL 3,117,542

ARRANGEMENT IN ZIG-ZAG SEWING MACHINES FOR SEWING BUTTON HOLES AUTOMATICALLY Filed March 26, 1962 2 Sheets-Sheet 2 United States Patent ARRANGEMENT IN ZiG ZAG SEWING MACHBNES FGR SEWlNG BUTTGN HOLES AUTOMATICALLY 'Emerich Schenkengel, Kaiserslantern, Pfalz, Germany,

assignor to G. M. Pfaif AG, Kaiserslautern, Pfalz,

Germany Filed Mar. 26, 1962, Ser. No. 182,361 Claims priority, application Germany Apr. 5, 1961 6 Claims. (Cl. 112-77) The present invention relates to zig-Zag sewing machines and is particularly concerned with the sewing of button holes by means of such machines.

More in particular the invention relates to an arrangement for sewing button holes automatically by means of a zig-zag machine which is provided with a presser foot having a sole that is movable in the direction in which the material is fed and which is driven by a control cam that rotates in steps.

In normal household zi -zag sewing machines known heretofore which were provided with an arrangement for sewing button holes, the material is fed by the conventional feeding arrangement which moves the material with the aid of a device referred to as a transporter. The sole of the presser foot which firmly rests on the material is provided with abutments, which by way of a mechanical or electrical control means move on the control disks for shifting the feeding device. This control, however, requires additional means which make the arrangement complicated and expensive. The feeding of the material by means of the transporter has also the disadvantage in view of the fact that the transporter is usually provided with teeth in the form of serrations, so that the amount of material feed obtained with the teeth in the two directions of sewing is different when sewing in different directions. This results in a different number of stitches being sewn per unit length. The discrepancy or disproportion between the stitch length in one direction with respect to the stitch length in the other direction can result in faulty setting of the stitch setting slide and therefore in even greater disproportion because of the extremely small feeding movement per stitch that is required for sewing button holes. One of the gimps of the button hole then has a different stitch density as compared to the other gimp, and as a result the button hole is unattractive in appearance.

In specific automatic machines which are used exclusively for making button holes, it is known to move the material by means of a feeding member which firmly presses down on the material. Such completely automatic machines, however, are only intended and suitable for making button holes. For that reason the problem of interchanging the button hole presser foot against other presser feet does not arise in this connection.

It is an object of the invention to simplify the means for automatically sewing button holes in normal zig-zag sewing machines used in the household and to eliminate the aforementioned shortcomings. Furthermore, an arrangement is to be provided which insures an equal amount of material feed by means of the feeding member in both directions.

In accordance with the invention the driving connec tion between the sole of the presser foot and the control disk or cam may be disconnected, and the driving arm which projects from the head of the sewing machine is retractable into the housing of the machine.

Iri this manner the button hole foot can be replaced in simplest fashion by normal presser feet. Moreover, the area adjacent the foot is free of oscillating parts during normal sewing, so that the seamstress need not be afraid of injuries to the hand or of damage to the machine.

3,ll7,542 Patented Jan. 14, 1954 A structurally simplified and economical embodiment of the control lever is made possible in that the retractable arm is made from a bent leaf spring and is slidably supported in a guiding slot of an arm portion of U- shaped cross section.

Furthermore, in accordance with the invention the control lever is provided with a plurality of bores opposite which corresponding bores are disposed in a support member connected with the housing of the sewing machine, where a pin inserted in opposite bores constitutes a link joint between the support member and the control lever. In this manner it is possible by simple change of the position of the pin to produce differently stepped button hole sizes.

A further object of the invention and details of the advantages provided thereby will become apparent from the following description of an embodiment illustrated in the accompanying drawings, in which:

FIG. 1 is a front View of the sewing machine provided with the new arrangement for the automatic sewing of the button holes,

FIG. 2 is a partial view of the machine taken from the top with the cover removed,

FIG. 3 is a perspective exploded partial view of the machine with the head cover removed and illustrating the removed arm cover as well as the support plate from the bottom, and

FIG. 4 is a section taken along the line lVIV in FIG. 3.

On the arm 1 of the sewing machine a support plate (FIG. 2) is mounted below the cover 2 which supports a lid 3. A shaft 5 is rotatably journalled on the support plate 4, and a control cam 7 having a cam groove 6 is secured to said shaft 5. Furthermore, two interchangeable control cams 8 and 9 which are rigidly connected with one another are journalled on the shaft 5. They are held in place by a nut 19. A pin 11, which is secured to the cam disks 8 and 9 and extends parallel to the axis of theshaft 5, engages a corresponding bore in the cam disk 7 below it and insures of the cam disks 8 and 9 being moved along by the shaft 5.

The shaft 5 is driven by a continuously adjustable stepby-step mechanism 12 (FIG. 3) which is drivingly connected by way of a thrust bar 13 and a double armed lever 14 to a conical cam-16 secured to the arm shaft 15 of the machine. The double armed lever 14 is biased by a helical spring 17 which at one end is secured to the lever 14 and at the other end to the support plate, in a manner that a roller 18 provided at the free end of the lever 14- is held in constant engagement with the cam 6.

The lever 14 is rotatably mounted at its hub 19 on a pivot shaft 29 which is secured to a slide member 21 which is movable parallel to the arm shaft 15. The slide member 21 is securedto and guided on the support plate 4 by means of when screws 22 which extend through longitudinal' slots 23.

The slide member 21 has a recess 24 into which enters a pin 26 mounted on a crank arm 25. The crank arm 25 is rotatably mounted by means of shaft 27 in the cover 2, which shaft extends through the cover and has a switching knob 28 (FIG. 1) at the upper outwardly extending free end. The support plate 4 is provided with a longitudinal aperture 29 (FIG. 3) of sufiicient length to enable the pin 26 to reach through unimpededly for operating the slide member 21.

A lever 3d (FIG. 2) which is rotatably journalled about a bolt 31 secured to the support plate 4 is provided with a projecting lug 32 which engages the control cam or disk 8. The lever 30 is linked at its free end with a force link bar 33 which is connected by means of an eccentric collar screw 34 to a lever arm 35 (FIG. .3) which cooperates in 3 a known manner with the mechanism for the stitch width control.

An angular lever 37 is rotatably journalled upon a further bolt 36 (FIG. 2) secured to the support plate 4 and is provided at one end with a cam follower 38 and connected at the other end with a linkage bar 39. The linkage bar 3 in turn is connected by means of an eccentric collar screw 40 to a lever arm 41 which cooperates in a known manner with the stitch centering mechanism.

Bolt 31 (FIG. 2) also pivotally supports a double armed lever 42, one arm 43 of which has a lug 44 which is guided in the cam groove 6 of the cam disk 7. The end 45 (FIG. 3) of the other arm of the double armed lever 42 is bent downwardly and supports a ball head 46.

A U-shaped angular member 47 is secured to the head of the machine which has a bridge portion 48 to which a stirrup 49 is threadedly secured. The bridge portion and the stirrup together form a support bearing 50 for a control lever 51 which at its upper end is provided with an eyelet 52 which encompasses the ball head 46.

The center part of the stirrup 49 and also the bridge 48 are provided with strips 53 and 54 which extend longitudinally of the control lever 51 to provide better guidance for the control lever 51. On the outside of the center portion of the stirrup 49 a vertically extending reinforcement member 55 is provided which engages a slot (not illustrated) in the head cover 56 (FIG. 1) of the machine.

The support member 50 (FIG. 4) is provided with a plurality of bores 57 which register with corresponding bores 53 in the control lever 51. A pin 5? having a manipulating knob which can be inserted as desired into registering bores 57, 5S constitutes the pivot point for the control lever 51. The control lever 51 has an arm portion 60 (FIG. 3) the longitudinal edges of which are turned up in U-shaped fashion to form the slide for a resilient arm 62 extending in the direction of the material presser bar 61 of the machine and which is provided with a longitudinal slot 63 for sliding in the arm portion 68 while it is bent over at the lower end to form a grip 64.

A presser foot 65 which is secured to the presser bar of the sewing machine comprises a shank as, a sole 67, a joint or pivot pin 63 and a roller 69. The shank 66 has two lateral lugs 79 supporting the pin 68 on which the roller 6h is journalled. The outwardly extending ends of the pin 63 project into elongated slots 71 on the turned up leg portions 72 of the U-shaped sole portion 67 while the roller 69 rests on the inner surface of the sole and imparts pressure to the sole by means of a presser foot spring (not illustrated).

One of the two side or leg portions 72 of the sole 67 is provided with a pin 73 onto which the arm 52 of the control or guide lever 51 may be hooked by means of a vertical slot 74 provided above the grip member 64, after being slidingly withdrawn from the arm portion 60.

The device operates as follows:

During operation of the machine oscillating movements are imparted to the double armed lever 14 by way of the cam 16 and roller 18 which are transmitted to the step-by-step mechanism 12 by means of pusher bar 13. As a result the control cams 7, 8 and 9* are driven or moved in steps. If the switch knob 28 is operated, the pivot shaft 29 of the double armed lever 14 is moved parallel to the arm shaft 15. The roller 18 is thus guided along the side of the substantially conical cam 16. As a result the magnitude of the feeding movements of the control disks 7, S and 9 can be varied continuously from Zero to a maxi mum in accordance with the eccentricity of the cam 16.

In order to produce a button hole the knob 23 is set for a small angle of rotation per step of the shaft 5. Arm 62 of the control lever 51 is pulled out and the sole 67 of the presser foot 65 slidingly moved until the pin 73 provided on the side of the leg portion 72 of sole 67 can be entered into the slot 74 of the arm 62. The machine is now set for button hole sewing.

The button hole seam can be started at any desired portion of the button hole. The cam groove 6 of the cam disk 7 at the same time imparts reciprocating movement to the sole 67 of the presser foot 65 with the material by way of the lug 44, double armed lever 42 and control lever 51. The needle bar stitch width is simultaneously controlled by the control cam disk 8 by way of lever 30, transmission bar 33 and lever arm 35, while the stitch center position is controlled by control cam disk 9 by way of hell crank lever 37, transmission bar 39 and lever arm 41 of the setting device for the stitch centering mechanism.

Upon completion of the closed button hole scam, the button hole is sewn up by bar tack stitches in a known manner, and the machine is in the initial position for making a new button hole.

The size of the button hole can be varied by selecting a different pivot point for the control lever 51 by changing the position of the pin 59 to different pairs of bores 57, 58. The distances intermediate the pairs of bores are chosen in a manner that button holes of the normal sizes can be sewn.

Having now described my invention with reference to the embodiment illustrated in the drawings, I do not Wish to be limited thereto, but what I desire to protect by Letters Patent of the United States is set forth in the appended claims.

I claim:

1. Device for automatically sewing button holes on zigzag sewing machines of the type having a machine head, a drive shaft, a needle bar disposed in said machine head operatively connected to said drive shaft, a needle bar oscillator disposed in said machine head in which said needle bar is slidingly supported, a presser bar disposed in said machine head substantially parallel to said needle bar and a presser foot secured to the lower end of said presser bar, said presser foot having a sole member mounted thereon for sliding movement transversely of said presser bar and having a connecting device, means for moving said sole member relative to said presser foot including a control lever extending generally parallel to said presser bar and having a portion detachably supporting said sole member on said connecting device, a stepby-step mechanism mounted proximate said machine head, a cam member on said drive shaft, means including a cam follower operatively linking said step-by-step mechanism to said cam member and means operatively connecting said control lever to said step-by-step mechanism.

2. Device for automatically sewing button holes on zig-zag sewing machines of the type having a machine head, a drive shaft, a needle bar disposed in said machine head operatively connected to said drive shaft, a needle bar oscillator disposed in said machine head in which said needle bar is slidin ly supported, a presser bar disposed in said machine head substantially parallel to said needle bar and a presser foot secured to the lower end of said presser bar, said presser foot having a sole member mounted thereon for sliding movement transversely of said presser bar and having a connecting device, means for moving said sole member including a control lever having a portion detachably supporting said sole member, a step-by-step mechanism mounted proximate said machine head, a cam member on said drive shaft, means including a cam follower operatively linking said step-bystep mechanism to said cam member and means operatively connecting said control lever to said step-by-step mechanism, said control lever being a double armed lever having one arm portion provided at its lower end with connecting means for engagement with said connecting device and having a rectractable portion in sliding engagemet with the other arm portion of said lever for telescop ing movement relative thereto.

3. Device for automatically sewing button holes on zig-zag sewing machines of the type having a machine head, a drive shaft, a needle bar disposed in said machine head operatively connected to said drive shaft, a needle bar oscillator disposed in said machine head in which said needle bar is slidingly supported, a presser bar disposed in said machine head substantially parallel to said needle bar and a presser foot secured to the lower end of said presser bar, said presser foot having a sole member mounted thereon for sliding movement transversely of said presser bar and having a connecting device, means for moving said sole member including a control lever having a portion detachably supporting said sole member, a step-by-step mechanism mounted proximate said machine head, a cam member on said drive shaft, means including a cam follower operatively linking said stepby-step mechanism to said cam member and means operatively connecting said control lever to said step-by-step mechanism, said control lever being a double armed lever having one arm portion provided at its lower end with connecting means for engagement with said connecting device and having a retractable portion in sliding engagement with the other arm portion of said lever for telescoping movement relative thereto, said one arm portion being defined by a leaf spring and the other said arm portion being of U-shaped cross section defining a sliding channel.

4. Device for automatically sewing button holes on zig-zag sewing machines of the type having a mach ne head, a drive shaft, a needle bar disposed in said machine head operatively connected to said drive shaft, a needle bar oscillator disposed in said machine head in which said needle bar is slidingly supported, a presser bar disposed in said machine head substantially parallel to said needle bar and a presser foot secured to the lower end of said presser bar, said presser foot having a sole member mounted thereon for sliding movement transversely of said presser bar and having a connecting device, means for moving said sole member including a control lever having a portion detachably supporting said sole member, a step-by-step mechanism mounted proximate said machine head, a cam member on said drive shaft, means including a cam follower operatively linking said step-by-step mechanism to said cam member and means operatively connecting said control lever to said step-by-step mechanism, said control lever having a plurality of bores, said device further including a pivot member mounted on said machine head and having a plurality of bores, and a pin engageable with different pairs of corresponding bores to provide a pivot support for said lever.

5. Device for automatically sewing button holes on zig-zag sewing machines of the type having a machine head, a drive shaft, a needle bar disposed in said machine head operatively connected to said drive shaft, a needle bar oscillator disposed in said machine head in which said needle bar is slidingly supported, a presser bar disposed in said machine head substantially parallel to said needle bar and a presser foot secured to the lower end of said presser bar, said presser foot having a sole member mounted thereon for sliding movement transversely of said presser bar and having a connecting device, means for moving said sole member including a control lever having a portion detachably supporting said sole member, a step-by-step mechanism mounted proximate said machine head, a cam member on said drive shaft, means including a cam follower operatively linking said step-bystep mechanism to said cam member and means operatively connecting said control to said step-by-step mechanism, said control lever being a double armed lever having one arm portion provided at its lower end with connecting means for engagement with said connecting device and having a retractable portion in sliding engagement with the other arm portion of said lever for telescoping movement relative thereto, said control lever having a plurality of bores, said device further including a pivot member mounted on said machine head and having a plurality of bores, and a pin engageable with different pairs of corresponding bores to provide a pivot support for said lever.

6. Device for automatically sewing button holes on zig-zag sewing machines of the type having a machine head, a drive shaft, a needle bar disposed in said machine head operatively connected to said drive shaft, a needle bar oscillator disposed in said machine head in which said needle bar is slidingly supported, a presser bar disposed in said machine head substantially parallel to said needle bar and a presser foot secured to the lower end of said presser bar, said presser foot having a sole member mounted thereon for sliding movement transversely of said presser bar and having a connecting device, means for moving said sole member including a control lever having a portion detachably supporting said sole member, a step-by-step mechanism mounted proximate said machine head, a cam member on said drive shaft, means including a cam follower operatively linking said step-bystep mechanism to said cam member and means operatively connecting said control lever to said stepby-step mechanism, said control lever being a double armed lever having one arm portion provided at its lower end with connecting means for engagement with said connecting device and having a retractable portion in sliding engagement with the other arm portion of said lever for telescoping movement relative thereto, said one arm portion being defined by a leaf spring and the other said arm portion being of U-shaped cross section defining a sliding channel, said control lever having a plurality of bores, said device further including a pivot member mounted on said machine head and having a plurality of bores, and a pin engageable with different pairs of corresponding bores to provide a pivot support for said lever.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,,117 542 January. 14 1964 Emerich Schenkengel It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column o line 8 after "control" insert we lever Signed and sealed this 9th day of June 1964.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J BRENNER Attesting Officer Commissioner of Patents 

1. DEVICE FOR AUTOMATICALLY SEWING BUTTON HOLES ON ZIGZAG SEWING MACHINES OF THE TYPE HAVING A MACHINE HEAD, A DRIVE SHAFT, A NEEDLE BAR DISPOSED IN SAID MACHINE HEAD OPERATIVELY CONNECTED TO SAID DRIVE SHAFT, A NEEDLE BAR OSCILLATOR DISPOSED IN SAID MACHINE HEAD IN WHICH SAID NEEDLE BAR IS SLIDINGLY SUPPORTED, A PRESSER BAR DISPOSED IN SAID MACHINE HEAD SUBSTANTIALLY PARALLEL TO SAID NEEDLE BAR AND A PRESSER FOOT SECURED TO THE LOWER END OF SAID PRESSER BAR, SAID PRESSER FOOT HAVING A SOLE MEMBER MOUNTED THEREON FOR SLIDING MOVEMENT TRANSVERSELY OF SAID PRESSER BAR AND HAVING A CONNECTING DEVICE, MEANS FOR MOVING SAID SOLE MEMBER RELATIVE TO SAID PRESSER FOOT INCLUDING A CONTROL LEVER EXTENDING GENERALLY PARALLEL TO 